Visual discrimination accuracy does not differ between nasal inhalation and exhalation when stimuli are voluntarily aligned to breathing phase

Neural dedifferentiation refers to an age-related phenomenon whereby brain functions that are localized to specific, distinct, and differentiated brain areas in young adults become less so as people reach more advanced age. Older adults tend to exhibit greater spread of cortical activation on fMRI during cognitive processing compared to younger adults, with evidence that this occurs during visuoperceptual processing. Some age-related functional changes are considered compensatory, but whether dedifferentiation is compensatory is not clearly understood. The current study assessed dedifferentiation and visual discrimination performance during simultaneous match-to-sample tasks from the Visual Assessment Battery (VAB) among 40 healthy middle-aged and older adults using fMRI. Task-relevant regions of interest (ROIs) were created in the dorsal stream for discrimination of spatial location, the ventral stream for shape, and an area encompassing V5 for velocity. Dedifferentiation, or less specificity in functional activation, was associated with greater discrimination accuracy and more years of education. Secondary analyses showed that reduced functional activation in task-relevant ROIs was associated with faster discrimination speed. Age was unassociated with functional activation. Results suggest that dedifferentiation is compensatory. Lack of age effects suggest that other factors beyond age, such as cognitive or brain reserve, may better predict performance when considering cognitive skills that are relatively stable as adults age, such as visual discrimination.

Download Full-text

Interindividual Variation in Fornix Microstructure and Macrostructure Is Related to Visual Discrimination Accuracy for Scenes But Not Faces

Journal of Neuroscience ◽

10.1523/jneurosci.0026-14.2014 ◽

2014 ◽

Vol 34 (36) ◽

pp. 12121-12126 ◽

Cited By ~ 23

Author(s):

M. Postans ◽

C. J. Hodgetts ◽

M. E. Mundy ◽

D. K. Jones ◽

A. D. Lawrence ◽

...

Keyword(s):

Visual Discrimination ◽

Interindividual Variation ◽

Discrimination Accuracy

Download Full-text

Visual Discrimination Accuracy across Reaction Time in Rats

Animal Behavior and Cognition ◽

10.26451/abc.07.01.03.2020 ◽

2020 ◽

Vol 7 (1) ◽

pp. 23-38 ◽

Cited By ~ 1

Author(s):

Daniel Kurylo ◽

Cindy Lin

Keyword(s):

Reaction Time ◽

Visual Discrimination ◽

Discrimination Accuracy

Download Full-text

X-Ray Microanalysis of Nickel and Cobalt Intensified Peroxidase- Antiperoxidase For Verification of Reaction Sites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100119168 ◽

1985 ◽

Vol 43 ◽

pp. 468-469

Author(s):

A. Angel ◽

K. Miller ◽

V. Seybold ◽

R. Kriebel

Keyword(s):

Reaction Mechanisms ◽

Visual Discrimination ◽

Osmium Tetroxide ◽

Ultrastructural Level ◽

Microscopic Level ◽

Electron Microscopic Level ◽

Electron Microscopic ◽

X Ray ◽

Insoluble Polymer ◽

Cytochemical Reaction

Localization of specific substances at the ultrastructural level is dependent on the introduction of chemicals which will complex and impart an electron density at specific reaction sites. Peroxidase-antiperoxidase(PAP) methods have been successfully applied at the electron microscopic level. The PAP complex is localized by addition of its substrate, hydrogen peroxide and an electron donor, usually diaminobenzidine(DAB). On oxidation, DAB forms an insoluble polymer which is able to chelate with osmium tetroxide becoming electron dense. Since verification of reactivity is visual, discrimination of reaction product from osmiophillic structures may be difficult. Recently, x-ray microanalysis has been applied to examine cytochemical reaction precipitates, their distribution in tissues, and to study cytochemical reaction mechanisms. For example, immunoreactive sites labelled with gold have been ascertained by means of x-ray microanalysis.

Download Full-text

Stimulus Ratio Effects on Speech Discrimination by Children and Adults

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3403.671 ◽

1991 ◽

Vol 34 (3) ◽

pp. 671-678 ◽

Cited By ~ 9

Author(s):

Joan E. Sussman

Keyword(s):

Discrimination Task ◽

Response Pattern ◽

Response Patterns ◽

Speech Discrimination ◽

Adult Group ◽

Discrimination Accuracy ◽

Formant Frequency ◽

Response Strategies ◽

Place Of Articulation ◽

Adults And Children

This investigation examined the response strategies and discrimination accuracy of adults and children aged 5–10 as the ratio of same to different trials was varied across three conditions of a “change/no-change” discrimination task. The conditions varied as follows: (a) a ratio of one-third same to two-thirds different trials (33% same), (b) an equal ratio of same to different trials (50% same), and (c) a ratio of two-thirds same to one-third different trials (67% same). Stimuli were synthetic consonant-vowel syllables that changed along a place of articulation dimension by formant frequency transition. Results showed that all subjects changed their response strategies depending on the ratio of same-to-different trials. The most lax response pattern was observed for the 50% same condition, and the most conservative pattern was observed for the 67% same condition. Adult response patterns were most conservative across condition. Differences in discrimination accuracy as measured by P(C) were found, with the largest difference in the 5- to 6-year-old group and the smallest change in the adult group. These findings suggest that children’s response strategies, like those of adults, can be manipulated by changing the ratio of same-to-different trials. Furthermore, interpretation of sensitivity measures must be referenced to task variables such as the ratio of same-to-different trials.

Download Full-text